Joint for connecting purlins and sag rods



March 31, 1970 c. H. FRASER 3,503,641

JOINT FOR CONNECTING PURLINS AND SAG RODS Filed Aug. 21, 1967 3Sheets-Sheet 1 7 FIGI Z 2 L g Y T +q 4 c. H. FRASER 3,503,641

JOINT FOR CONNECTING PURLINS AND SAG RODS March 31, 1970 '3 Sheets-Sheet2 Filed Aug. 21. 19s? FIGS FIG.7

March 31, 1970 C. H. FRASER JOINT FOR CONNECTING PURLINS AND SAG RODS 3Sheets-Sheet 5 Filed Aug. 21. 1967 FIG-.8

FIG-.9

MW'W 1/ I -b LL14 L L 41.

United States Patent Office 3,503,641 Patented Mar. 31, 1970 US. Cl.287189.36 3 Claims ABSTRACT OF THE DISCLOSURE A sag rod and a method offixing same to a purlin in the fabrication of a roof structure, the sagrod having resilient means at each end thereof, each resilient meansbeing compressed on that end of the sag rod being passed into anaperture in a purlin to engage a slot in the sag rod with the purlin.

This invention relates to an improved method and means for straighteningpurlins by sag rods in the fabrication of roof structures.

When the roof of a metal building is being fabricated, it is thepractice to fit purlins of sheet metal, formed into either Z or Icross-section, to the roof girders so that the roofing material may belaid. These purlins are fitted at predetermined intervals and runhorizontally across the sloping roof girders. 'Each purlin may have tobridge as much as 20 feet from one girder to the next and therefore,although the cross-section of a purlin is such that it will withstandexcessive deformation, some sagging of the purlins where they are notpositively supported by a girder will take place.

To eliminate this sagging of a purlin, it has been proposed to employsag rods which connect adjacent purlins. The uppermost purlin is heldagainst sagging by a tie connected to its opposite purlin on the otherslope of the roof and these two purlins hold each other against sagging.These two purlins are then used as datum purlins for holding the othersstraight and parallel. The known sag rods are normally metal rods screwthreaded at each end which pass through holes in the purlins and arefixed by nuts. This arrangement necessarily involves the positioning ofwashers and nuts and tighening of the nuts, and it is left to thejudgement of the workman as to when the purlin has been straightened andlies parallel with the datum purlin. Also, considerable time is involvedin tightening the nuts. Further, it is a laborious job to dismantle thesag rods for re-use and generally the sag rods are left within thestructure.

There is therefore a need for a sag rod and a method of positioning thesame which may be done rapidly and with accuracy without the workmanhaving to exercise his judgement on its correct positioning. Also, it isdesirable to have as few parts as possible which are unconnected beforeerection.

According to the present invention there is provided a method of fixinga sag rod in relation to a sheet metal purlin in the fabrication of aroof structure, including passing one end of a sag rod through anaperture in a purlin or in a bracket fixed to the purlin therebycompressing resilient means between the sag rod and one side of theaperture and thus tending to force the sag rod to the opposite side ofthe aperture and passing said one end of the sag rod further through theaperture until a shoulder of the sag rod abuts one side face of thepurlin, whereupon the said resilient means moves the sag rod so thatsaid opposite side of the aperture enters a slot in the sag rod.

The invention also includes a method of fixing a series of sag rods tostraighten a plurality of sheet metal purlins in the fabrication of aroof structure, including the steps of fixing the upper end of a firstsag rod to a given datum purlin, passing the lower end of the first sagrod through an aperture in a lower purlin until a shoulder on the firstsag rod abuts one side face of the lower purlin and fixing said lowerend within the aperture, passing the upper end of a second sag rodthrough a further aperture in the lower purlin until a shoulder on thesecond sag rod abuts the other side face of the lower purlin and fixingsaid upper end within the further aperture, passing the lower end of thesecond sag rod through an aperture in a still lower purlin until ashoulder on the second sag rod abuts one side face of the still lowerpurlin and fixing said lower end within the aperture, and continuing thepositioning and fixing of successive sag rods in a similar manner toretain successive purlins straight and parallel with the datum purlin.

The invention also includes a sag rod comprising a predetermined lengthof channel section being similarly formed at each end to presentoutwardly facing shoulders at a given distance apart and a slot near toeach end of the channel section, each of said shoulders forming theinner side wall of one of said slots and resilient means at each end ofthe channel section near to each slot to retain part of a purlin withinthe slot.

The invention will now be more particularly described, by way of exampleonly, and with reference to a accompanying drawings, in which:

FIG. 1 is a plan view of part of a sag rod constructed in accordancewith the invention;

FIG. 2 is an end view of the sag rod of FIG. 1;

FIG. 3 is a side elevation of the sag rod of FIG. 1;

FIG. 4 is a view similar to FIG. 3 showing the sag rod partly connectedto a purlin;

FIG. 5 is a view similar to FIG. 4 showing the sag rod fully connectedto a purlin;

FIG. 6 is a front view of a purlin with two sag rods connected thereto;

FIG. 7 is a side view of the purlin and sag rod of FIG. 6;

FIG. 8 is a plan view of the purlin and sag rods of FIG. 6; and

FIG. 9 is a side view of a modified form of fixing of a sag rod to apurlin.

Referring first of all to FIGS. 1 to 5, a sag rod includes a member ofchannel section 1, the length of which is predetermined by the distancebetween adjacent purlins as fixed in position in the fabrication of aroof structure. The channel section 1 is shaped similarly at each end,only one of the ends being illustrated in the drawing. The channelsection 1 is provided with a slot 2 one side wall 3 of which forms anabutment. The end of the channel section 1 is tapered at 4 and a leafspring 5 is fixed to the upper surface of the channel section 1 by arivet 6, the outer end of the leaf spring 5 being turned over at 7 toprevent the leaf spring pivoting about the rivet 6. As will be seen, oneend of the leaf spring 5 is anchored to the channel section 1 by therivet 6, whereas the other end 8 of the leaf spring rests on the uppersurface of the channel section 1.

The various stages in fixing a sag rod 1 to a sheet metal purlin 9 areshown in FIGS. 4 and 5. The purlin 9 is provided with an aperture 10 andthe end of the sag rod 1 is passed through the aperture 10, this beingassisted by the taper 4 of the end of the sag rod. In

moving the sag rod 1 to the position illustrated in FIG. 4 in relationto the purlin 9, the leaf spring 5 will be compressed against one sideof the aperture, thus urging the sag rod 1 firmly against the other sideof the aperture 10. On passing the sag rod 1 further through theaperture 10, one face of the purlin 9 will abut against the shoulder 3and, due to the pressure of spring 5, the sag rod 1 will be urged intothe position shown in FIG. 5, namely with part of the purlin 9 withinthe slot 2.

The abutments 3 at each end of the sag rod 1 are at a predetermineddistance apart and therefore, when both ends of the sag rod are fixed toadjacent purlins, the purlins will be at a predetermined distance apart.Thus, if a datum purlin is in its correct position on the roofstructure, so therefore will the adjacent purlin be at the correctdistance from the datum purlin. Also, if the datum purlin is straight,by use of the sag rod in accordance with the invention, the successivepurlins can also be made straight and parallel with respect to the datumpurlin. How this is done is illustrated in FIGS. 6 to 8 from which itwill be seen that each purlin 11 is provided with two apertures 12 and13. A first sag rod, for example, sag rod 14, is fixed at its upper endto the datum purlin and then the lower end of this sag rod 14 is fixedto the next purlin by the method described in relation to FIGS. 1 to 5.A second sag rod 15 then has its upper end 6 in aperture 13 and thelower end of sag rod 15 fixed within an aperture in the next lowestpurlin. In this manner all the purlins along the roof structure may beheld straight and parallel with the datum purlin and with each other.

As will be appreciated, the method of fixing a sag rod to a purlin asabove described necessitates the sag rod being at right angles to thepurlin. In forming a sloping roof structure, however, the two top-mostpurlins are joined together by a tie and the sag rod of the presentinvention may be used as this tie. Because these two topmost purlins areat an angle to each other, some means must be provided for attaching theties thereto and such means is illustrated in FIG. 9. A purlin 16 hasfixed thereto, by bolts 17 and 18, a bracket 19 which carries a shaft 20which also carries as further bracket 21, the shaft 20 allowing pivotalmovement between brackets 19 and 21 so that an aperture 22 withinbracket 21 may be moved to lie other than parallel with the purlin 16.In a manner similar to that previously described a sag rod or tie 23 maybe fixed within aperture 22. If both the topmost purlins 16 are providedwith brackets 19 and 21, the sag rod or tie 23 may extend between thesetwo purlins 16 and hold them straight and parallel.

It will be appreciated that the leaf spring 5 above mentioned may bereplaced by any other form of resilient means which will enable a sagrod to be located and held in relation to a purlin as above described.Also, the resilient means may not be attached to the sag rod but may beassociated with the aperture in the purlin.

I claim:

1. A joint comprising a panel having an aperture therein and a rodmember having an end thereof extending through and projecting beyondsaid aperture, said rod member 'being tapered along one side thereoffrom the extremity of said end toward said aperture, a transverse slotin said rod member on one side thereof adjacent the inner end of saidtaper for receiving a first edge portion of the aperture therein, theside wall of said slot remote from said taper extending transverselyoutwardly beyond the opposed side wall to define a stop shoulder, anddeformable resilient means secured to said rod member on the sidethereof opposite to said slot, said resilient means being compressedbetween said rod and a second edge portion of said aperture toresiliently bias s'aid transverse slot into engagement with said firstedge portion.

2. A joint as claimed in claim 1 wherein the deformable resilient meanscomprises a leaf spring.

3. A joint as claimed in claim 1 wherein the transverse slot is on thesame side of said rod member as the taper.

References Cited UNITED STATES PATENTS 2,377,334 6/1945 Feindel 287-20 X2,644,063 6/1953 Zikmund et al. 248-223 X 2,901,845 9/1959 Whisler --8.3X 3,088,760 5/ 1963 Codlin.

3,337,198 8/1967 Casella 52667 X RAMON S. BRITTS, Primary Examiner US.Cl. X.R.

